Flights to and from Shanghai International Airport Co Ltd. and 11 other airports in east China are facing major delays until mid-August due to military exercises, according to an official micro blog.

The posting by Beijing's public securities bureau did not give any details about the “large scale” military exercises.

It said flights would be affected from July 20 to August 15.

Officials from the Civil Aviation Administration of China can not be reached immediately for comment.

A Shanghai Airport investor relations executive declined to comment.

Airports in east China are among the busiest in the country. Last year, Shanghai's two mega airports - Pudong and Hongqiao - alone handled 82.8 million passengers, or about 11 percent of overall passenger throughput, according to official statistics.